Canoga Park-based Pratt & Whitney Rocketdyne, the aerospace and defense manufacturer which develops rocket propulsion and engine systems, has been acquired by GenCorp in a deal worth $550M, the firms said this morning. GenCorp is acquiring Pratt & Whitney Rocketdyne from United Technologies Corporation. Pratt & Whitney supplies a range of systems to the government and commercial markets, including the main engines for the Atlas and Delta launch vehicles.